Retainer for piercing tool



May 2, 1961- w. H. PECK RETAINER FOR PIERCING TOOL Filed March 30. 1959 United States Patent 2,982,556 RETAINER FOR PIERCING TOOL William H. Peck, 314 N. Center St., Royal Oak, Mich.

Filed Mar. "30, 1959, Ser. No. 802,943

3 Claims. Cl. 279-19 This invention relates. to a tool retainer for retaining a tool, such 'as a punch, in operative relation with a pneumatic hammer of the percussion type.

The tool herein illustrated is shown as a punch for piercing holes in sheet metal members, after which self tapping screws are threaded into the hole.

In forming holes through the sheet metal member in this manner, the punch is provided with a sharp pointed piercing nose which is pierced through the metal by a series percussion blows at the opposite end of the tool. The pointed piercing nose spreads the metal and flares, a flange on the back side surface of the metal, thereby increasing the thread area for the screw, and since the nose is driven into the metal by the hammer blows it is tightly held in the hole causing resistance to its removal. The operator is required to tip the axis of the tool from one side to the other to remove the tool, resulting in distribution of the hole.

It is an object of the present invention to provide means within the tool retainer, cooperating with the shank of the tool, for producing oscillatory movement to the tool when a pulling force is applied to the tool in removing it from the hole, thereby facilitating removal of the tool without distortion of the hole.

Another object of the invention is to provide a tool a the tool with respect to the axis of the retainer.

A further object of the invention is to provide a retainer for holding the tool which may be manufactured as a unit assembly and press fitted in the operating end of the hammer.

Other objects and advantages of the invention will more fully appear from the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a side elevational view of a pneumatic hammer showing the improved retainer and punch applied thereto;

Fig. 2 is an enlarged cross sectional view of the retainer showing the shank of the tool inserted in the retainer;

Fig. 3 is a top plan view of the ball cage sleeve showing the tool shank therein and the ball race slot; and i Fig. 4 is a cross sectional view taken on .line 4--4 of Fig. 2.

Referring to the drawings, I have shown a pneumatic hammer 10, of the percussion type, having a barrel 12 and a handle 14. The handle has a connection 16 for communication with an air pressure line 18 connected to a source of pressure, notshown. A control is shown at 20 for admitting the air pressure to the operating parts of the hammer which are of conventional construction.

The tool, herein illustrated as a punch 22, is received in the open end of the retainer, more clearly shown in Fig. 2.

The tool retainer includes a ball cage sleeve 24 having an axial bore therethrough for receiving the tool 22 which has a sliding fit therein. The outer diameter of l ate'nted May '2, 1961 the ball cage sleeve 24 is provided with axially spaced grooves 26 for receiving snap washers 28 having an Outer diameter greater than the outer diameter of the ball retainer sleeve. One end of the ball cage sleeve has its outer diameter reduced, as at 30*, providing a shoulder 32 which limits the inward movement of the retainer against the outer end of the barrel 12 when the reduced end 30 is press fitted into a bore 34 in the open end of the barrel 12. 1

Ball receiving slots 38 are formed in the wall of the ball cage sleeve 24 for reception of balls 36 having a diameter greater than the wall thickness of the ball cage sleeve 24. The slots have side walls which are preferably tapered to prevent the balls from passing entirely through the slots. The slots are arranged radially opposite'each other and each have portions 38' and 38" sloping in reverse helical directions. These slots 38 form raceways -for directing the balls 36 through a tortuous path.

A sleeve 40, slidab'ly fitted to the outer periphery of the ball cage sleeve 24, is axially movable between washers 28 and a spring 42, positioned in a counter-bore 44,- between the washer 28 at the right and the shoulder 46, formed by the counterbore, urges the sleeve 40 against the washer 28 at the left. The inner diameter of the sleeve 40 is provided with an annular groove 48 adjacent its left hand end for permitting the balls 36 to be moved radially outwardly when the sleeve 40 is moved to the right against the resistance of the spring 42. When the sleeve is in the position shown in Fig. 2 the balls 36 are held radially inwardly by the inner surface of the sleeve 40 between the groove 48 and the shoulder 46. V

The tool retainer is a self contained unit which may be applied to the open end of any pneumatic hammer.

The tool herein illustrated is a round, hard steel member having a straight shank portion 50 with a sharp pointed punch portion 52 projecting from one end there-' pressed recesses 58 in the peripheral surface of thetool shank. These recesses have a depth approximately equal to one thirdof the diameter of the ball 36 and are formed on a radius equal to the radius of the ball 36.

The retainer assembly is applied to the pneumatic hammer by press fitting the reduced end portion 30 in the open end of the barrel 12. To insert the tool, the

sleeve 49 is slid on the ball cage sleeve 24 toward the pneumatic hammer which positions the groove 48 over the balls 36. The tool is then slid into the bore through the ball cage sleeve 24. The inserted end 56 of the tool moves the balls radially outwardly into the groove 48 permitting the tool to be fully inserted into operative position with the balls received in the depressed recesses 58. The spring 42 then forces the sleeve 40 toward the outer end of the ball cage sleeve 24 with the cylindrical inner surface of the sleeve 40 retaining the balls in the slots 35. The tool is free for limited axial movement within the bore through the ball cage sleeve 24, determined by the length of the grooves or slots 38, but is retained therein by the ends of the slots in the portions 38' and 38". Since the slot portions 38' and 38" extend in opposite helical directions, the tool is oscillated in two directions during its axial movement in either direction relative to the retainer and pneumatic hammer.

When piercing a hole through a metal member, the

. 3 operator presses the pointed end 52 of the tool on the metal; This pressure forces the tool inwardly of the hammer and when the hammer is operating the percussions within the hammer force the tool outwardly, driving the pointed end 52 through the metal. The balls 36, carried by the tool and guided in the slots 38, 38 and 38", cause the tool to be oscillated in two opposite directions as it pierces the hole. When the operator withdraws the tool from the hole by a pull, the action causes the tool to be slid outwardly relative to the retainer and hammer. Due to reversed helical slot 38, the tool is given a double oscillatory movement to loosen the point 52 in the hole formed in the metal.

It will be understood that one or more balls may be used and that various changes, including the size, shape and arrangement of parts, may be made without departing irom the spirit of the invention, and it is not my intention to limit its scope other than by the terms of the appended claims.

I claim:

1. A retainer for a straight shank tool including a ball cage sleeve having a straight bore through and a straight outer peripherial surface for press fit reception in the 1 barrel of a pneumatic hammer, axially spaced grooves in the outer periphery of said ball cage sleeve, snap ring washers received in the grooves, an outer sleeve slidably carried on the outer periphery of said ball cage sleeve between said snap washers, the inner periphery of said outer sleeve having an annular groove therein, a compression spring between one of said snap washers and one end of said outer sleeve, a ball receiving slot having portions sloping in reverse helical directions formed in the wail of said ball cage sleeve, a ball in said slot, in combination with a straight shank having an annular recess formed in its outer peripherial surface for receiving said ball.

2. A retainer for a straight shank tool comprising, a ball cage sleeve having a straight bore therethrough for reception in the barrel of a pneumatic hammer of the percussion type, a continuous slot having portions sloping in reverse helical directions formed in the wall of said ball cage sleeve, a tool shank having axial movement in the bore of said ball cage sleeve, a ball receiving recess in the outer periphery of said tool shank radially opposite the slot in saidsleeve, a ball in said slot and ball receiving recess in 'said tool shank, and means for positioning the ball radially in said slot.-

3. A retainer for a tool for use in a pneumatic hammer of the percussion type, comprising a sleeve having a bore for reception of a straight shank tool attached to said pneumatic hammer, a helical slot in the wall of said sleeve for the reception of a ball, a ball in said slot having a diameter greater than the thickness of said sleeve wall, means for positioning said ball radially whereby said ball is free for radial movement out of said bore or partially projected into said bore, in combination with a tool having a shank adapted for sliding fit within said bore, and provided with a sphericai recess in its outer periphery for the reception of said ball when said ball is projected in said bore by said projecting means, whereby rotary movement is imparted to said tool by the ball riding in said helical slot when the tool is reciprocated in said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS Fishcher Feb. 11, 1958 

